I currently have accumulated
8L Motul 300V 0W40
4L M1 0W40
2L M1 5W50
8L Selenia touring 5W50
10L Total quartz racing 10W50
3L Total quartz racing 10W60
1L BMW Super power 5W40
4L Yacco galaxie 15W50
5L Shell Helix HX7 10W40
10L Shell Rimula R6M 10W40
And at least 2L of various leftover, which I keep in the trunk just in case...
I also have some gearbox fluid
3L Castrol Dextron III atf
5L Castrol Syntrax 75W90
4L Castrol Syntrans 75W90
3L Motul gear 300 75W90
And I'm still wondering what to put in my cars... I have enough oil for a lifetime I guess, but most is on the heavy side.
I arrived at a point that most of my friends can come and ask for a OC kit, and I have it "in stock"!
I recently donated many "outdated" oil from the nineties to my uncle, which has a 1934 Renault Primaquatre sport, and did a lot of OC. My GF is very tolerant, lol!