assuming we are talking about the "hemichromis bimaculatus" type jewels, you have actually gotten a soft water african. so technically you should stick to other soft water type fish. this pretty well sticks you to south americans. i've had mine with convicts, they have similar temperaments and sizes. if you only keep one the aggression levels should be fairly low too, so just about any smaller soft water cichlid would work fine.
i have also kept mine with some of the more common hard water africans when i was new. this *could* lead to problems tho, not to mention one type or the other won't ever be really thrilled with your water parameters.
my old tank was setup with: inhabitants: jack dempsey, auratus, blue zebra, breeding jewel pair, turquoise jewel pair, pictus cat, striped raphael, spotted raphael, 3 upside down cats (synodontis nigriventis?), 1 apple snail
but this wasn't the best route to go.
if you can find the turquise jewels, they have a really awesome color morph. it's like an iridescent blue instead of the red.
good luck whatever you choose.