I have some weird and wonderful ones. A lot are OS, during lockdown i completed my set of the last issue 1" to the mile. I also have a complete set of series 1 1:50000. I'm about 2/3rds of the way through the set of second series. I also have lovely set of pre war Barts in slip cases.
I aquired a lot of large format plans when a local college was disposing of theirs - they are from all over the country.
The odd ball things that I collect are the AA route guides where if you wrote to them they would send detailed routes of how to get from A to B via Z. I have a fascinating set starting in Market Drayton and going to the Western Isles - they are pre-war.