agent
alterant
alterative
alterer
ancestor
announcer
antecedent
architect
author
avant-garde
bellwether
buccinator
bushwhacker
catalyst
catalytic agent
creator
developer
explorer
ferment
forebear
foregoer
forerunner
front runner
frontiersman
fugleman
groundbreaker
guide
harbinger
herald
innovationist
introducer
inventor
lead runner
leader
leaven
maker
messenger
modificator
modifier
original
originator
pathfinder
pioneer
point
precedent
precursor
predecessor
producer
scout
stormy petrel
conceiver
mastermind
adventurer
agitator
assailant
contributor
discoverer
educator
enthusiast
entrepreneur
essayist
ethnologist
experimenter
financier
marauder
mathematician
naturalist
philanthropist
revolutionist
scientist
strategist
theorist
thinker