I'm curious if there's an online resource that can tell me my XMR wallet balance by just the public key / address?
I know that I can install XMR GUI wallet for that, but it has two major drawbacks:
1) I need to actually download and install software when all I need is the balance.
2) Once installed it tries to download what appears like the entire blockchain that may take days with my connection. And I'm not talking about wasted space on the hard drive needed for that.
you can use whats called a "block explorer"
you can find one for most any coin
one for Monero is here: https://moneroblocks.info/
enter your public addy (payment ID) in top right to check your balance

no dl's needed