Merge Boost

The Merge Boost (MB, known as Million Merge Boost before the update 8.4) is a feature introduced in the 7.4 Update, which can be unlocked at a x450 Stars Tree Upgrade and gives huge boosts. It was changed in 8.4, giving x1.01 every 100k merges instead of x1.05 every 1 million.

Unlock
It is unlocked at a Tree Upgrade, available at x450 Stars: "Get a x1.01 Magnet Boost every 100k Merges".

Effect
Each 100k (100.000) Total Merges you've done, no matter if you had the upgrade before or not, you will get 1% more magnets from all sources, similar to the v3.

The reason why this is considered one of the most helpful upgrade: It is the only magnet giving thing in the whole game that works multiplicative. Instead of an additive 1% / 100k merges which would give a 2% boost after 200k, 3% after 300k etc., it puts those 1% on the production every 100k. Example: You get 1000 magnets / magnet in a storm, have 3.5 million merges and then unlock the MMB; instead of 1350 you would get 1416.

Areas which are affected by this gain
All magnet productions get benefits from this Upgrade, just like Scrapyard v3. This includes:
 * Magnets from storms
 * Magnets from Level Ups
 * Magnets from Team Leagues
 * Magnets from Converting
 * ...and many more

Trivia

 * The Merge Boost was suggested by Brickman, who has the most stars and total merges as of August 2020. The exact suggestion was: "Get 5% overall magnet boost per completed million total merges (multiplicative)"
 * It worked differently before the update 8.4: It gave a 5% multiplicative boost every 1 million merges (Million Merge Boost) instead of 1% every 100k (Merge Boost).