Clark Ashton Smith, C.L. Moore, Michael Shea, Caitlin Kiernan, Stephen King, Ruthanna Emrys, and Victor Lavalle. Probably a few others, too. Ramsey Campbell with comments about his Severn Valley stories getting the kind of development that Lovecraft did with his New England.
I would touch on HPL as a historically important instigator whose revolting biases make his work mostly of scholarly interest, and that it’s better to read folks who took his ideas and ran with them to places Lovecraft didn’t and couldn’t go. Robert Bloch, Fritz Leiber, Brian McNaughton (now there’s a dude who needs to be talked up more), Sylvia Moreno-Garcia, Gemma Files, Premee Mohammed, Hailey Piper.
Um, this list would need a lot of trimming and explaining to actually be worth including in something D&D-like. I’d give maybe three authors a short paragraph each, and a sentence each to about a dozen more, for a total of about one column.