Factorio 2.1 port of Threadwork by Alvin (CoolFreeze23). Click a belt and the whole connected line gets marked for upgrade, to targets you pick. A panel (Ctrl+Shift+T) sets your belt, underground, splitter, loader and inserter targets; the Thread Upgrader (Ctrl+Shift+U) walks the connected thread and your bots swap everything over, inserters included. No tier lists and no upgrade chains: tiers are detected from belt speed, so any belt mod works. Underground pairs are skipped if the target can't span the gap. Right-click cancels. Also includes a Thread Remover.
Providing the player with new tools or adjusting the game interface, without fundamentally changing gameplay.