Lugia is correct and I am a bit of an LFO and envelope junkie with all sorts of modulation modules: Quadrax, Kermit, Batumi, Radar, Malekko Quad Envelop, Acid Rain Technology Maestro. Many have combo modes that do LFO and EG in button settings. Some are pure LFO or pure envelope like my basic Doepfer LFO and Doepfer ADSR modules. I like do cool modules bang for buck so a super modulator like Kermit can output 4 LFOs or envelopes or random voltages or combo of these things. Some advanced clock modules like Pamela's New Workout even have LFO and envelope mode features as well. For learning as a beginner, I recommend getting a simple LFO module and a simple envelope generator module and clock. Figure out how to use LFO with envelopes and VCAs to modulate things. Then move to a do cool combo super modulator like the ones I mentioned above. Most important: have fun! Eurorack is a super expensive hobby so if you are not having fun then you are doing it wrong :-)