Alternatives are silkworms, hornworms, butterworms, zophobas m (superworms), and cabbage lopers.
There is a common misconception on this forum that Butterworms should be treated like waxworms. Yet all nutritional analysis I've read indicates Butterworms dont contain more fat than superworms but are far richer in calcium than superworms. The real downside to butterworms is NOT their fat content, but that you can not gutload them.
I offer butterworms quite regularily, it probably averages out to once or twice a week.
Superworms must be gutloaded and should be lightly calcium dusted too. I offer them several times a week, in combination with other feeders. Some people have successfully used these as a staple.
When I have silkworms, I feel comfortable offering these every other day or even ever day in combination with other feeders.
Hornworms are expensive to get (where I am) so I only offer these now and then, but if i had access to less expensive ones I'd use them weekly.