Welcome aboard.
Lock collecting is a wide open area of choice. You have door locks, safe locks, padlocks, keys and specialty locks. Specialty locks are like locks for a special application beyond just locking something up. Example a time lock keeps a safe locked until the timer runs out of time on it. The list I have given is just a small part of what there is out there. Have a look around as there are many locks on this site that are very nice.
So I will start with the question of what type of lock were you looking for?
There are many brands that are well known such as Yale here in the states. There are well known locks from all parts of the world. Some that are not well known are very important to the lock world for making something that later was common in locks. So just being famous isn’t just the only thing to look for. Milner would be a good example of this.