I'm Dgraider. I'm not very high elo in League of Legends and far from being the best Rumble out there. I just thought I'd make this guide because there aren't really any good Rumble text guides out there. There are plenty of builds/styes that I didn't mention here(i.e. DoinB's predator mid(not advised unless you play with a 5 stack), the korean Rumble support(just take the comet for runes and go full damage with spelltheifs), Conqueror mid(okay to play for fun), Rumble top(we don't talk about this - too many bad matchups), Went's style of Rumble, etc.).

Looter is a high elo NA Rumble(Challenger). You can google him if you want more information, but his video guide is the best Rumble guide you will find on the internet.

For his style of play(always electrocute if mid). Buy Sorc boots over liandrys, but liandrys first item and from there buy what you need(or if you don't know what you need, Zhonyas isn't a bad item)

Danguiz is a high elo Rumble player whose build style I learned from the Rumble discord(you can join off of the Rumble subreddit if interested)

Rush Protobelt if you think you can kill or need it to close the distance, otherwise rush Rabadons(this will give you as much damage as you would have had if you are behind despite the terrible gold efficiency here)