That's interesting, First Cycling and PCS both say 59, usually PCS quote numbers that are lower.
The crits are included in the 100, not in the 59
so the First Cycling list has
6 Elite international championships
2 National elite titles
3 WT GCs
5 WT one days
16 WT stages (inc 1 TTT) (First Cycling lists 24 WT wins, but counts 23 in citing that data)
9 2.Pro/HC GCs
3 1 .Pro one days
14 2.Pro/HC stages
1 2.1 GC (but that's a Hammer event)
4 2.1 Stages (but 3 of them are Hammer events, marked as TTTs but not really)
1 1.1 one day
Thus far, 64 wins to fit into the 59 UCI wins (presumably excluding 4 Hammer results and the UEA Tour TTT)
Then there are the included Junior events:
4 International titles
2 Nationals
3 J-2.NC GCs
5 J-2.NC stages
2 J-2.1 GCs
5 J-2.1 stages
5 J-1.1 one days
5 Jr one days
2 Jr stages
So 33 Junior wins, the categories of which I don't claim to understand.
That makes 97, then
Gullegem Koerse, marked as an Amateur KP
and Criterium Aalst and Criterium Oostrozebeke, both marked as Amateur 1.CRT
So yes, 100 can be found, but it relies of some odd inclusions.
Not that the unquestionable 59 elite + 33 juniors are to be sniffed at.
By a similar First Cycling reckoning, Pogacar's next win will be his 100th, but his list includes a cyclocross race at NE level, a 2.2 GC, an amateur 1.12 race, 3 U23 wins and 2 crits .