My wife had a Dell Axim. And I have a Palm IIIx. I don't think the question will end up being "What apps are recommended for it?" Rather, "Is there anywhere I can even FIND an app for it?" IIRC, the AXIM runs some outdated (and probably no-longer-supported?) version of a Windows mobile OS. Being Windows, apps were probably not free (not many of them anyway), and probably came with some type of copy-protection or register-to-enable scheme. Finding one of these old apps in the first place, let alone getting it "registered" and running on your AXIM, may be quite the task. Also, IIRC, the AXIM uses a removable battery pack. Any original AXIM batteries will probably be long worn out and useless. Can you even buy a new battery pack for it these days? Possibly a 3rd-party vendor from China might still make one. But if you have one of those, charge it with care. Old charging technology plus LiIon batteries plus made-in-China could spell disaster. I would charge it in a flame-proof metal container, away from anything combustible, and under near-constant supervision. If the batteries aren't LiIon, then that would be safer. I can't remember how the AXIM cradle hooked up to the computer. Was that via a serial port? Does your computer even HAVE a serial port?

PDA's were really neat gadgets in their day. But they are obsolete now. They've been gone for, gosh, about a decade now? These days, PDA's are to computing what Betamax is to video. I hope you can get yours working and doing something useful. That would be a fun project. But I would consider it more of a "hobby project" than something that will end up being real-world useful. You can probably buy an el-cheapo brand new tablet for $50 (American dollars) that will run rings around the AXIM. I seem to remember paying several hundred dollars for my wife's AXIM back in the day.