Is there any way to discover/ find out the public key of a specific bitcoin address? If not, are there any available tools online to help find the public key of a specific bitcoin address?
The only way is to see if any outputs for that address have been spent before, and then looking at the spending transaction(s). Those spending transactions will contain the scripts and public keys for that address.
Otherwise, no, it is not possible. Addresses are constructed by hashing public keys or scripts, and one of the key properties of hash functions is that they are not reversible. So you cannot take the hash encoded by an address and compute what was hashed (i.e. the public key or script).