You could probably find a coin, medallion, token, and/or doubloon to commemorate every flight, mission, or program to have ever had the goal of launching an object — human or otherwise — into space.
In fact, you could probably locate several for each.
With such a wide selection to choose from, one approach is to collect only flown medallions or those minted using metal that was carried into space.
Robbins medals
Considered by many collectors as the most desirable of all the flown medallions, the Robbins (named for the company responsible for their minting) are created for, purchased by, and only available to the astronauts.
Columbia • STS-107
To date, none of the 39 flown silver medallions have been recovered. This example, minted post flight, is number 242 of 515 produced for the families and friends of the crew. (Not actual size.)
Discovery • STS-114
Due to minting issues, delivery of the "Return To Flight" medals was delayed by over a year. This is number 54 of an unspecified number of unflown silver (Not actual size.)
Referred to by the title of the NASA office tasked with their issuing, the Manned Flight Awareness medals mark one of the rare instances when the agency used flown hardware to create mementos.
Each medal was minted in part from metal flown aboard the mission for which it commemorates.
NASA presented these medals to their employees and contractors (typically accompanied by a certificate or card) whose work helped to make the mission a success.
Medals as pictured are not actual size.
Apollo 8
"In appreciation for your contribution to the Apollo Saturn project the Apollo 8 crew carried metal in this medallion on man's first flight to the Moon"
Year issued: 1968 Mint: Barco Mint of New Orleans No. Minted: 200,000 Flown metal: half-inch sphere of aluminum
Apollo 11
"This Medallion contains metal from spacecrafts Columbia and Eagle, that took Astronauts Armstrong, Aldrin and Collins on their historic Apollo 11 mission that resulted in the first landing of man on the Moon."
Year issued: 1970 Mint: Barco Mint of New Orleans No. Minted: 200,000 Flown metal: LM: pulley clamp; CM: heatshield bolt
Skylab
"This medallion contains metal that traveled through space on the world's first space station -- the U.S. Skylab -- on which astronauts Conrad, Kerwin, Weitz, Bean, Garriott, Lousma, Carr, Gibson and Pogue opened a new era in the uses of space"
Year issued: 1974 Mint: [unknown] No. Minted: 100,000 Flown metal: 16mm film canister
Apollo Soyuz
"This medallion contains metal from both Apollo and Soyuz that joined together in the first International manned space mission on July 15-24, 1975"
"Thank you for your contribution toward making the Approach and Landing Tests of the Space Shuttle Orbiter successful. We would like you to have this memento made, in part, of metal taken from the Enterprise."
"Thank you for your contribution toward making the world's first orbital flight of the Space Shuttle STS-1 possible. We would like you to have this memento made, in part, of metal taken from the Columbia.
"This medallion commemorating international cooperation in space contains metal from the U.S. Space Shuttle Atlantis and the Russian Space Station Mir."
Year issued: 1996 Mint: Galaxy Medals, Inc. No. Minted: [unknown] Flown metal: [unknown]
STS-88
"This coin, containing medal from the Unity node flown on mission STS-88, commemorates the cooperation of nations and the deployment of the first U.S. element in building the International Space Station December 4-15, 1998."
Year issued: 1998 Mint: Galaxy Medals, Inc. No. Minted: 60,000 Flown metal: two pieces of metal cut from the skin panel on "Unity" (Node 1); one piece measuring 6"x2" and the other measuring 6.75" x 2.25" and both 1/2" in thickness
STS-98
"This coin, containing medal from the U.S. Laboratory module flown on mission STS-98, commemorates the deployment of another element in building the International Space Station February 2001."
Year issued: [unknown] Mint: Galaxy Medals, Inc. No. Minted: [unknown] Flown metal: [unknown]
STS-114
"This coin contains medal flown aboard Space Shuttle Discovery, STS-114, July 28-August 2, 2005"
Year issued: [unknown] Mint: Winco International No. Minted: [unknown] Flown metal: two metal ingots carried in Official Flight Kit
Miscellaneous medals
Sometimes confused as a Manned Flight Awareness issue, the following medallions were also minted with flown metal or other source material.
NASA 50th
"This edition contains medal flown aboard a space shuttle mission."
Year issued: 2009 Mint: Winco International No. Minted: 5,592 Flown metal: [unknown]
Apollo 7
"This medallion contains metal from the Apollo 7 spacecraft flown by Wally Schirra, Donn Eisele and Walt Cunningham. October 11-22, 1968."
Issued by: Frontiers of Flight Museum Year issued: 2008 Mint: [unknown] No. Minted: 500 Flown metal: fragments from Kapton polymide tape and 16mm data acquisition cable
Apollo 8
"This 50th Anniversary medallion contains metal from most of the aircraft Eastern has flown since the Pitcairn Mailwing and from the Apollo 8 spacecraft as well."
"This medallion commemorating the 30th anniversary of the Apollo Program contains metal from a Saturn V launch tower used to send Americans to the Moon."
Year issued: 1999 Mint: Galaxy Medals, Inc. No. Minted: Al: 101,000; Bronze: 10,775; Silver: 750 Flown metal: n/a
Apollo 40th
"This medallion contains medal flown to the Moon on Apollo missions."
Year issued: 2009 Mint: Winco International No. Minted: [unknown] Flown metal: [unknown]
Apollo 13
"This set of medals was struck on a special lot of sterling silver containing a small amount of metal returned from the epic Moon voyage of Apollo XIII"
Issued by: The Franklin Mint Year issued: 1970 Mint: The Franklin Mint No. Minted: [unknown] Flown metal: an unspecified number of silver medallions minted by The Franklin Mint and carried aboard Apollo 13
Apollo 14
"This mini-coin is made from a special melt containing silver that was carried to the Moon on the flight of Apollo 14"
Issued by: Franklin Mint Collector Society Year issued: 1971 Mint: The Franklin Mint No. Minted: 129,449 Flown metal: 24 of 200 sterling silver medallions carried to lunar orbit
Viking 1
"This medallion contains material from Viking which landed on Mars July 20, 1976"
Issued by: Martin Marietta Year issued: 1976 Mint: [unknown] No. Minted: [unknown] Flown metal: N/A
Skylab
"This medallion contains authentic material from Skylab - traveled one billion miles in outer space"
"First flight of an international laboratory developed in Europe and dedicated to space research for the benefit of mankind."
Issued by: NASA and European Space Agency Year issued: 1983 Mint: [unknown] No. Minted: [unknown] Flown metal: Entire medal was flown in space Note: Unflown medals also exist and were distributed
STS-41D
"This medallion contains metal flown aboard Space Shuttle Discovery Mission 41-D, August 1984, carrying industry's first representative in space, Charles Walker."
Issued by: McDonnell Douglas Year issued: [unknown] Mint: [unknown] No. Minted: [unknown] Flown metal: [unknown]
STS-89
"A portion of the metal used in the creation of this medallion was flown aboard the Space Shuttle Endeavour on the STS-89 mission which docked with the Russian Space Station Mir."
Issued by: MSFC Space Shuttle Project Office Year issued: [unknown] Mint: [unknown] No. Minted: [unknown] Flown metal: [unknown]
Maiden Flight
"These medallions are made of metal blended with materials used in the first launch of Space Shuttle [Columbia, Challenger, Discovery, Atlantis, Endeavour]."
Issued by: Port Canaveral Year issued: [unknown] Mint: [unknown] No. Minted: [unknown] Flown metal: N/A - pieces of the launch pad
World Space Congress 1992
"This paper-weight contains material flown aboard Space Shuttle Discovery, STS-42; Soyuz TM-11; and a stony meteorite recovered near Forrest Australia."
Issued by: NASA, NPO Energia and SSI Year issued: 1992 Mint: [unknown] No. Minted: [unknown] Flown metal: [unknown]
40th Anniversary of Americans in Orbit
"Commemorating the 40th Anniversary of Americans in orbit, this medallion contains metal from Mercury Atlas launch pad 14."
Issued by: Astronaut Scholarship Foundation Year issued: 2002 Mint: [unknown] No. Minted: 2500 Flown metal: n/a
Moon Rocket Engine Tests
"This commemorative pin contains metal shavings from original J-2 and F-1 engines tests at NASA Stennis Space Center"
Issued by: NASA Stennis Space Center Year issued: 2006 Mint: Winco Interational No. Minted: [unknown] Flown metal: n/a
SSME Tests
"Stennis Space Center marks 30 years of testing Space Shuttle Main Engines. To commemorate this historic milestone, this coin contains metal shavings from a Space Shuttle Main Engine tested at SSC."
Issued by: NASA Stennis Space Center Year issued: 2005 Mint: Winco Interational No. Minted: [unknown] Flown metal: n/a
Yuri's Night (Aluminum, Bronze, Silver)
"This coin contains Soyuz and Space Shuttle flown metal."
Issued by: Yuri's Night Year issued: 2006 Mint: Galaxy Medals, Inc. No. Minted: [unknown] Flown metal: STS-42 flown insulation; STS-94 flown insulation; Soyuz TM-32 flown washer
