Currently, the two primary ones for intensifying something are totemo which is standard Japanese and metcha which is slang and a lot closer to “hella” or “lit”. You use these before the thing you’re describing in a sentence. As for other exclamation words, all I can think of is yabbai which is a general catch all that can mean good or bad things. It’s very multipurpose and can range from meaning “crap” to “yikes” or “woah”