Is there a service that shows up used addresses containing a substring? Is there a service that searches the blockchain with a string or possibly a regex to find out a set of possible addresses, say if I only know a half of a public address?
https://goochain.net had an option to search bitcoin addresses in the explorer with a string that has few initial characters according to this link: https://bitcointalk.org/index.php?topic=808066.msg9179505#msg9179505
The block explorer is dead and I have not seen this option in any other explorer used right now.