What units should I get next?

I've been into 40k for well over a decade now but could only afford the lore until a couple years ago when I bought my first World Eaters models. I have Kharn, because he's Kharn, and I have the World Eaters combat patrol. But now I'm looking to expand my army now, what units should I get next?

I'm not trying to build a massive army just yet, but I would like to eventually build it up to around 2,000 points. Not looking at tournaments or being overly competitive but any ideas would be appreciated.