Aaaah now I'm going to have some fun in a "if I were you" list
Frankly, I'm a little dumbfounded... it looks like you're letting some of your best lenses go... I don't own many of those, so feel free to ignore my thoughts on the matter
(yes= I own it, no = I don't own the lens)
15mm f/4 (no), but contemplated the purchase a lot (then went the zoom way), and if I had it I would absolutely keep it
21mm f/3.2 (no), but I'd love the FoV just like the 15mm... I'd let it go grudgingly
40mm XS (yes) everywhere! go-to small-bag traveling kit : Sigma 10-20/3.5, the XS and maybe the SMC-M 100/2.8
50mm f/1.4 (no) a specialty lens, ok... maybe sell it
90mm (no) isn't this one a good macro lens? is the 100mm really better? just curious.
18-250mm (no) sell
18-55mm (yes) sell
20-40mm (no) I would love to have this one... how can you possible sell it? small, WR, a "prime with some zoom"...
70-300mm (no) sell
50mm f/1.8 (no) makes sense to keep it... also not worth much in terms of money but a lot photographically so...
100mm f/3.5 (no) makes sense to keep just one macro... don't know which one so I'll keep my mouth shut about it
10-17mm (no) as I said I own the Sigma 10-20mm... an UWA is unreplaceable so, yeah
18-135mm (no) that's a real Swiss Army knife... so ok to keep it
55-300mm (yes) your best option on the tele side, so ok
In short, I'd only sell the 21mm, the 50/1.4, the 18-250mm, the 18-55mm, the 70-300mm and one macro lens (not sure which one).