I don't think any forks are literally ALL carbon, you wouldn't get a fork with carbon dropouts.
No idea whether you can get ones with a carbon crown. Probably not.
You can get forks that are literally all carbon, including the crown and dropouts, including Easton EC90 SL that I have. I don't refit the wheel often enough for the carbon dropouts to bother me. The EC90 might just take a 28mm tyre without mudguard - but there'd be no wobble room. It'd be dangerous if the wheel goes even slightly out of true.
However, I'm happy enough to use carbon forks with alloy crowns and steerers too, when they're recent-ish models from reputable makes. I recommend the Tifosi ones with mudguard eyelets. These can take a 28mm tyre, though a mudguard, if used, might need to be cable-tied in place rather than using the usual fixings.