Multiple Caret Booster is a Visual Studio extension making multiple carets even more useful feature. It contains these three features:

Lets say you have multiple carets with a selection. Then you will copy your selection into clibboard (CTRL+C). Then you will move your carets somewhere else and paste copied text (CTRL+V). Without this extension Visual Studio pastes all lines of selection at every caret position. Madness... With this extension a paste command does exactly what you would have expected: Pastes corresponding copies of selections to corresponding caret positions.

Multiple carets can be created through matching some unique same text among lines. Sometimes there is just no same and/or unique text and that is when two new commands can come in handy. Just place your caret somewhere and then press SHIFT+ALT+'L' to place a new multiple caret on a next line. Or press SHIFT+ALT+'K' to remove last multiple caret. Just as almost the same as with standard "next-matching" aproach with SHIFT+ALT+'<' or '>' keyboard shortcuts.

Just make multiple caret selection anywhere and pres SHIFT+ALT+S to replace all selections with a number/character sequence based on value in first selection.