I struggle to even work out what my dream lens list is. If I just include lots of lenses I guess it isn't so hard, but I'd rather limit the number lenses and use what I have, than have too many sitting on the shelf getting almost no use. However, then I really struggle to work out what lenses I want! Anyway, my dream lens list would be something like:
35 f/1.4 - very happy with my Sigma Art
A relatvely small 40ish or 50ish lens, f/2 or wider, to use when I want a very small and light set up.
Samyang 85 f/1.4 (or an equivaelent of the Sigma 85 f/1.4 DG DN for E mount) - it may not be as good optically as the Canon RF 85 f/1.2, but the size and weight mean I expect I would use it a lot more than the Canon. (Or maybe a high quality fast 50 instead? Or go the other way, to a 135 f/2 or 135 f/1.8? I always struggle to decide which primes I really! I think an 85mm would probably make sense though, given other lenses I'd put in my kit.
24-70 f/2.8 (IS) ... or maybe 24-105 f/4 IS ... or maybe 24-105 f/4 IS + 28-70 f/2 ... or maybe 24-70 f/4 IS? My 24-70 f/4 IS has served me well, but I don't expect I will doing any more very long hiking trips anytime soon, or for that matter any other travel where keeping gear small and light would be particularly important, so I'm wondering if another option might be better for me now.
70-200 f/2.8 IS - I really like the idea of the relatively compact size of the RF lens. Given the price of the RF though, an equivalent of the Tamron 70-180 f/2.8 for E mount would be fine.
16-35 f/4 IS or similar ... maybe something like the Tamron 17-35 f/2.8-4. Not a lens I expect I would use that much, so I want something relatively small and light so it is easy to carry as an "extra" lens.
I could easily add other lenses to a wish list, eg a 100-400 of some description (again, portabiity would be a key factor for me for this lens) and a 135 f/2 or 135 f/1.8 spring to mind, but even the list above is 6 lenses, which I think is plenty for my use. Maybe I should just run with 24-70 f/2.8, 70-200 f/2.8, 35 f/1.4, and maybe a 40 pancake, and call it done?!