Split Keyboards
Ergonomic Split Keyboards
If you're looking for an ergonomic keyboard that fits the curve of your fingers better, you'll want to check out the Iris, with its columnar stagger.
Other great choices include ortholinear keyboards like the Nyquist and FoldKB. The BFO-9000 is perfect if you need a lot of keys.
Traditional Split Keyboards
If you would like to stick with a more traditional keyboard layout with less of a learning curve, you'll want to get the Sinc keyboard.
If you don't need a function row at the top, then the Quefrency will be a good option for you. The Cepstrum is also good if you want have a low-profile keyboard.