Check licence and sourceavaliability of the games from the following 
sites and if possible implement them:

https://astrobattle.com/
https://botsnscouts.sourceforge.net/index.php3
https://wouter.fov120.com/cube/
https://d1x.warpcore.org/
https://icculus.org/d2x/
https://www.scorpioncity.com/djgame.html
https://dossizola.sourceforge.net/
https://egoboo.sourceforge.net/
https://epiar.net/
https://www.nongnu.org/feuerkraft/
https://www.geocities.com/~elan_feingold/Software.html
https://www.movement.uklinux.net/fscktris/fscktris.html
https://gccg.cjb.net/
https://icculus.org/freespace2/index.php
https://www.floot.demon.co.uk/lincity.html
https://www.linux-games.com/castle-combat/
https://www.majik3d.org/
https://mantigua.sourceforge.net/
https://www.hut.fi/~jtpelto2/nethack.html
https://www.head-crash.com/orbit/index.html
https://openparsec.sourceforge.net/
https://www.planeshift.it/
https://www.pygame.org/shredwheat/solarwolf/
https://redpixel.sourceforge.net/redpixel.html
https://reaper3d.sourceforge.net/
https://www.lynxlabs.com/phobiaIII/index.html
https://robotournament.sourceforge.net/
https://www.scummvm.org/
https://sixdays.sourceforge.net/index2.phtml
https://slashem.cjb.net/
https://starshiptraders.com/
https://www.methane.fsnet.co.uk/
https://loser.sourceforge.net/
https://www.planetblood.com/qblood/
https://tuxaqfh.sourceforge.net/
https://uwadv.sourceforge.net/
https://universe.sourceforge.net/
https://vegastrike.sourceforge.net/
https://wod.sourceforge.net/
https://www.xevil.com/
https://page.inf.fu-berlin.de/~mkrueger/xcrillion/
https://xpired.sourceforge.net/
https://possibleworlds.cjb.net/
https://www.racer.nl/

08:37PM <tcr> kasc: Let me describe a possible end situation (that I'd really like): Having a
        bootable CD (or more) which boot smoothly, and there's a graphical login where you can
        choose between all games available on CD (cool would be with description and
        screenshot). Savegames etc. can be stored at a floppy...