West Indian or Key Lime is considered clonal from seed. I've seen a lot of different plants in Nth Qld, including in the wild. The fruit size and shape on individual plants can vary.
Tahiti Lime is essentially seedless. Infrequent seeds that I have grown are fairly variable lime like plants. Some are very weak and never progress. None have fruited yet.
True Lemon seedlings I have grown seem fairly true to type, with some slightly variable.
Rough Lemon produces identical seedlings, suitable for rootstock production. Again if a bunch of Rough Lemon rootstocks sucker and fruit, the fruit can be fairly variable in size and colour ( canary yellow to reddish ).