I don't know any names of techniques but I've been in speech therapy my while life and elementary was so much fun just because i had that class make sure they feel comfortable sometimes you might need a one on one instead of a group always be patient and relaxed but that's pretty obvious also you gotta get games game that are also for speech that'll help them relax and also get the therapy they need sadly i still stutter its not as bad but its still verrrry noticable but ill always cherish my time in my elementary speech class