Techoblade uses a Tightvault Revamp texture pack as of 2021. It previously used a wide variety of packs like WarV2 or TimeDeo's 2K pack.
This texture pack itself was created with PvP (Player vs Player) mode in mind. With using a PvP texture pack in Minecraft, there are a lot of little details that make a huge difference.
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One of the smallest but most important details is the transparent inventory bar. This allows you to see your screen a bit more, which can be crucial when fighting enemies on a PvP server.
It also features custom armor and weapon design added by the creator. You can see an example of what the Diamond Armor Set looks like in-game in the image below, but only when you put it on. It is much less tiring for the eyes.
Screenshot by Pro Game Guides
The amount of FPS (frames per second) you get from using a certain texture pack should be high to provide the fastest possible reaction in any PvP mode. That's why these textures are vanilla-based, so most blocks don't change at all.
Technoblade also uses a slightly modified version of this pack with a custom reticle. The Tightvault Revamp Pack was created by a popular YouTuber called "Tight". If you are looking for a heavy texture pack focused on PvP, try the Tightvault Revamp pack, you might like it.
For more Minecraft articles, guides, and news, be sure to check out What is Honey for in Minecraft? on Pro Game Guides.