No actual Roman would ever have said the Latin equivalent of 'catchall'. However, it does mean 'all-inclusive', so why not create one such as 'omni-inclusum'?
I did a little research to find out how old the word 'catch-all' was in English - never mind Latin - and found it dates back only to the 1830s. As matter of interest, in that earliest appearance, it was referred to as an 'omnium gatherum'...all gathered together, as it were. So, my created word wasn't that far from that.