Docs had a kind of low-powered, actually apologetic find and replace tool before that could only do whole-document, every-instance replacements. Now it's a bit more familiar, with one box for the finding text (or regular expression), one for the replacement, and buttons and shortcuts (Ctrl+F, Ctrl+G for next) that can replace items one-by-one:
That's just a writing tool, though. The new drawing app, found by hitting "Insert," then "Drawing" from the top menus, works on text documents, spreadsheets, and presentations. It's easy to figure out and doesn't require any special software (at least on SVG-supporting browsers like Firefox, Chrome, or Opera), but, as Google Operating System points out, you have to "save" the drawing by hitting the "X" in the upper-right, which doesn't seem like what you want to do.
Drawing on your creativity in Docs [Official Google Docs Blog]