Can I make a sponge cake without sugar?
You may want to look into quick bread recipes instead.
Examples of quick breads include muffins, scones, coffee cakes — often made sweet, but savory versions certainly exist. The primary difference is whether or not there's any sugar, and what sort of additional flavors are mixed in (such as fruits or chocolate in  sweet quick breads, cheese or meat or herbs in savory quick breads).
There are quite a lot of &quot;basic quick bread&quot; recipes available, and so I'll let you search on your own rather than post links which may go dead. Just make sure you look for a version that involves oil (and milk/buttermilk) instead of butter; some sweet sponge cake recipes get texture impacts from creaming butter and sugar together, which you couldn't do without sugar.