When you perform a search, the first match is highlighted. Additional matches have subtle border around them. In the definition for a color scheme, can the additional-matches style/border color be adjusted?
Actually, that would work out fine. I too have found it hard to find the caret, as well as the additional search items, using the Monokai Bright color scheme. Brightening up that color would help them both out. I am going to try and tweak that. I will post the tweak in here if I do it.