Do you have any idea how do I verify the tokens, if I can't find its smart contract address? (e.g. URAllowance, eHealth First)
You are asking how to be sure that token X is not a faked copy of token Y (from which you don't know the correct contract address) ?
Did i understand you correctly?
If this is the case, you can't. The only way to verify that the token is the original one is by knowing the contract address of the original one.
But to be honestly.. if you don't even know the contract address of the original token (and are not sure whether the one offered is fake or not), it probably is better to NOT accept it as collateral.
A token whose contract address can't be found out.. can't be worth much (if anything at all).
Regarding your 2 mentioned tokens:
URAllowance:
Seems to be a scam for me. They claim to give a '30% bonus' if you deposit ether to a given address. This address hasn't received anything at all.
Additionally there is no smart contract or anything. A simple money grab. Those tokens (if they have setup a smart contract at all) can't be worth anything.
eHealth First:
Doesn't have any link to their smart contract.
Tokens can be bought by contacting them via email. This sounds shady.
I can't imagine these tokens will be worth anything.