ToME: the Tales of Maj'Eyal

Possibly in other modes too.

If you could "drop shadow" the ^ or alternatively darken the background of the tile with a trap on. Or some identifying mark on the tile that is easily visible. For instance a small white T in the top corner of a trap tile.

Can we get them more visible?

Some monsters are hard to see as well. Green Worm Masses on a green background are a big offender.

I agree with both. Shift-T helps you find the monsters, but those traps only show up as yellow squares on the minimap (already hard to distinguish from the grey walls), and if you don't see them there, you're very unlikely to see the green-on-green caret (^) on the main map.

Also, I believe it's the black bear is invisible (black on black) when in the Old Forest.

The black bear is just dark gray. You should turn tactical mode on anyway. You won't miss any monsters that way.