Microwave oven transformers (MOTS) can be used for powering tesla coils. they have an output voltage of ~2500V and power ratings from 300-1500W. As their voltage is quite low for tesla coil use they are quite often used in pairs to give 5Kv.
MOT’s are current regulated by a small steel shunt which can be removed (usually fairly easily) to allow much higher throughput.
The output of a microwave oven transformer is LETHAL