Hmm, this is a nice one.
Aladdin's Ring. Most people have only heard remixes of the original story but in 1001 Nights, Aladdin had two genies. The Djinn of the Ring was somewhat less powerful than the Djinn of the lamp but the difference as insignificant for any task less than taking over the world (specifically it can be overruled by other Djinn, that's really its only weakness), which happened to be the evil African's goal. The ring also granted unlimited wishes so a pretty good deal.
Palm-sized bottle of Qi pills. ROB probably has a few varieties so I'll go with whichever both turns me into a cultivator and grants the most BS power, which are both pretty common in Cultivator fic so I'll just browse the selection. This will grant enormous personal power and a relatively easy path to immortality, and only grows even more BS with time.
Brooch of Number Numbing. Okay yeah, I have a genie for utility and I'm a cultivator with hax even by the standards of other cultivators, I don't need more power and this thing is hilarious. It's a DnD item that you wear as a brooch, and while you wear it anybody you interact with forgets how numbers work. Like you can tell them five is less than three and as long as you wear the brooch, they won't be able to refute it and will just accept that's how numbers work. In-game it's mostly used to cheat at haggling but consider the implications in the modern day, of f'rex making a YouTube video where you claim to have more likes than all other accounts combined and everybody who sees the video agrees, or futzing with the WEF by waltzing in and rewiring their understanding of basic math. There are countless options for immense pranks with it to a ridiculous degree, and as a Cultivator it could be extremely useful if I happen to meet an elder to explain to them that my five years of cultivation are far longer than their quarter-million years, and have made me far stronger than they could possibly be in such a short time.