¶ Overview
In the vast majority of cases for a 100% speedrun with a full squad, the best boosters are the Four Horsemen. Other boosters are more niche but are still suitable in certain cases.
The boosters in the last row are useless for speedrunning so this page won't even cover them (for now).
For a solo run, the Expert Extraction Pilot booster saves a significant amount of time. The Muscle Enhancement and Experimental Infusion boosters improve mobility but are especially useful if you are on foot. For a solo run where Fast Recon Vehicle is the main mode of transport, the Pelican Expert Extraction Pilot booster is more suitable.
¶ The Four Horsemen
¶ Hellpod Space Optimization (HSO)
What it does: Spawn with full supplies
Worth taking for speedrun?: YES
Saves the team the call in time for supplies at the beginning and allows them to steer their hellpods at the start to split up more efficiently
A must pick for most runs except maybe in a very fast mission like Blitz: Search and Destroy where you don't even care about most squad members having full supplies
¶ Experimental Infusion
What it does: 12.5% to 15% damage resistance and movement speed bonus while using a stim (buffs last 9.46 seconds). Fills screen with "drug effect" that zooms out FOV and upps contrast with yellow borders at edge of screen
Worth taking for speedrun?: Yes if there is room for it in a team's loadout and doesn't blind players
The only booster that directly impacts movement speed other than Muscle Enhancement. The buff lasts long enough for a significant time save even with just the 4 stims given at the start of a mission. Damage resistance is also nice for playing riskier and faster.
Worth noting that the visual effect can make it very difficult to see on certain biomes at certain times of day (Vernen Wells by night, Ustotu, Menkent, etc.). Might be worth skipping if a team member complains they cant see anything with their computer setup
¶ Expert Extraction Pilot
What it does: Reduces the extraction timer by 30% (1m 24s instead of 2m and 2m 06s instead of 3m with Complex Stratagem Plotting).
Worth taking for speedrun?: YES
Whether playing multiplayer or solo, this booster is essential for achieving the best times. On an excellent multiplayer scouted seed, the entire map can be cleared before Pelican touches the ground, even with this booster.
¶ Muscle Enhancement
What it does: Increased movement speed through any terrain or effects that slow (uphill/downhill, sand, snow, acid slow, bushes, etc.)
Worth taking for speedrun?: YES unless the map is a Megacity one (as there is no environmental elements. In this case, the Stamina Enhancement booster is more appropriate).
Most effective way to increase speed during the "walking simulator" portion of Helldivers 2. All biomes have elevation changes and various other environmental effects that slow down players, and most big time sinks during a run are while walking over the natural terrain.
It is also the best way to reduce the slow effect some Terminids inflict, way more effective than Motivational Shocks (which only reduces slow by 0.7 seconds!).
¶ Niche boosters
¶ Firebomb Hellpods
What it does: Increases the impact force and damage radius of all Hellpods (including resupply, sentry, support weapons, Helldivers, etc.) as well as inflicting fire damage. It will ragdoll players who are close enough
Worth taking for speedrun?: Yes, but only in very specific cases
This booster is mainly used in low-level runs and Any% runs where death rounds are used to destroy objectives.
¶ Stamina Enhancement
What it does: increased stamina bar, faster regen of stamina overall (around 30% longer sprint time from full bar in 50 armor, from 29 seconds w/o to 38 seconds w/ booster). Makes stamina recovery 2s faster.
Worth taking for speedrun?: Yes, instead of Muscle Enhancement on a Megacity map.
Outside of Megacity maps, it's not a must-have since stims or managing stamina through well-timed sprints can often make the lower stamina bar and recovery a non issue, especially given that you can sprint for quite a while without having even recovered the full bar.
¶ Vitality Enhancement
What it does: the exact numbers are not well-known, it but increases damage resistance including headshot damage reduction
Worth taking for speedrun?: Yes for missions with a lot of direct or risky engagements like Eradicate Automaton Forces/Terminid Swarm
Can let you take a faster route or kill enemies faster because you can take more hits from the enemy. Not always worth it if you're pretty much avoiding all enemies though in a very short mission like Destroy Command Bunkers or Blitz: Search and Destroy
¶ Dead Sprint
What it does: allows Helldivers to continue sprinting at the cost of health. Drains approximately 3.6% health (or ~1% with Vitality Enhancement) per second spent sprinting. Allows 25 seconds of continuous sprinting once out of stamina, and stops once health reaches 5%.
Worth taking for speedrun?: No, unless the situation requires an extremely long running time that cannot be shortened and without the loss of health being a concern
Pretty much a sidegrade to the Stamina Enhancement booster, which isn't a top tier one for speedrunning. It offers more sprint time, in exchange for the risk of being at low health. Also fills your screen with blood effects that can make it difficult to see.
¶ Credits
Helldivers Wiki for some of the booster icons and information.