My credential management tool has ~300 credentials in it, of which I use roughly 10% frequently, there is no way for me to remember these, without creating a sc

My credential management tool has ~300 credentials in it, of which I use roughly 10% frequently, there is no way for me to remember these, without creating a scheme which someone could eventually reverse given enough of my leaked credentials (so far about 15% of services I use have had breaches using weak hashes, and these tend to end up in public). Such a scheme would also have to support password rotation (for services which are breached, or which expire credentials) If I am going to store them somehow, an encrypted blob seems to handily beat pen and paper. The only scheme I can think of that would be strong would be one that is tool-assisted and given a set of password requirements (length, allowed characters, etc.), a domain, a master key, and an incremental counter, derived keys and formed passwords on the spot, but I'd still need to remember the criteria for each site, and the counter positions, and keep those secured... so whats a few more bytes?