and a list of trustworthy wallet providers for these Alt coins?
I think this script (
https://github.com/ymgve/bitcoin_fork_claimer) is what you're looking for, it support various altcoin, but it uses Python 2.7 (which reached EOL/end of life) and only have CLI/terminal option.
Electrum fork for these altcoin is an alternative, but you need to verify the source code or trust the developer.
I reckon most people has already forgotten about these coins and they just destroyed the wallets. (I hope not)
Or they don't care because they don't have much Bitcoin or the value of the altcoin is too small for them. There's also privacy concern from sending to same address (exchange in this case) or make single transaction with all your addresses.