The Palm devices were PDAs produced from 1996 to 2007 by Palm Computing. Although it was a pioneer in this field, poor management and growing competition from smartphones ultimately brought the Palm line down. It was succeeded by webOS. Almost all Palm OS games have been ported to iOS and Android devices, and since most games for Palm are no longer sold they're ridiculously hard to find.
If you're a collector who seriously wants to play PDA games, your best bet is the Tapwave Zodiac, a handheld game console that ran Palm OS and had a few exclusive titles of its own.
Sidescrolling racing game that's very similar to Elasto Mania for PC. Unlike most racing games, you have to be slow and deliberate to clear the levels instead of simply going fast.
Raise fish that drop money, while protecting them from invading "alien" fish.
Like a futuristic version of 2D Zelda games. The art is DeviantArt tier, but the rest of the game is solid.
You play as a member of the Luftwaffe attacking a Soviet base. There's a decent amount of content and multiple ships to choose from.
Elite clone. You start out in a small ship in a giantic galaxy, where you can trade and smuggle goods, attack other ships and upgrade your own ship. Every planet has its own economy, level of technological advancement and form of government. It was remade for iOS and Android under the name Dark Nova, but its visual improvements have the side effect of making text hard to read. Not to be confused with the FPS of the same name.
Basically Pirates! for Palm OS.
Basically Starcraft for Palm OS. Games for Palm OS aren't known for their originality.