Useful despite people being dumb - Magpul Industries B.A.D. Lever

The bad lever catches a lot of flak for allegedly causing negligent discharges. There is a slight risk of having your finger end up on the trigger with continued pressure after using this to close your bolt. However I primarily use the bad lever to hold my bolt open. This allows me to keep my right hand on my pistol grip and use my left to manipulate the charging handle.