There's ▲: ▲ and ▼: ▼

Don't forget the ∧ (logical and) and ∨ (logical or) characters, that's what I use for indicating sort direction: HTML entities ∧ & ∨ respectively.

There's always a lowercase "v". But seriously, aside from Unicode, all I can find would be &darr, which looks like ↓.

An upside-down circumflex is called a caron, or a háček.

It has an HTML entity in the TADS Latin-2 extension to HTML: ˇ and looks like this: ˇ which unfortunately doesn't display in the same size/proportion as the ^ caret.

Or you can use the unicode U+30C.

˅˅˅˅˅˅˅˅˅˅˅˅˅˅˅˅˅˅˅˅˅

 ˅˅˅ Hǝɹǝ,s ɐ ɯɐʇɔɥᴉuƃ sǝʇ˙ ˅˅˅
 ˄˄˄ Here's a matching set. ˄˄˄

˄˄˄˄˄˄˄˄˄˄˄˄˄˄˄˄˄˄˄˄˄

"Actual size": ˅˄˅˄  
_{(more info)}

Edit: Another Option...

⋁⋁⋁⋁⋁⋁⋁⋁⋁⋁ _{^{Unicode #8897 / U+22C1 (info)}} named N-ARY LOGICAL OR

⋀⋀⋀⋀⋀⋀⋀⋀⋀⋀ _{^{Unicode #8896 / U+22C0 (info)}} named N-ARY LOGICAL AND

"Actual size": ⋁⋀⋁⋀