Project64, Mupen64, and are great examples, because they all have a folder in their directory named "Plugin". It is not without its share of issues to this day, however. You should upgrade or use an alternative browser. GlideN64 is the best plugin available. You need a Gameboy game and a save file from the same game for the Transfer Pak to work, but do note that that emulation is far from perfect and won't work properly with some games.
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