SELF-FOUND BIRDS
Two hundred would probably take some doing in the UK, without a lot of travel and luck, but it’s possible if you get to go further afield (even if it’s only a beach holiday in Spain, travel restrictions permitting). So, no twitching, and no looking at your bird club’s sightings page. It will improve your ID skills enormously, especially in picking birds out of flocks (you’d probably need to find the likes of American Wigeon among Wigeon, for example).