Australian electronic visas don't appear in your passport - they are just on their computer system. However, they do still stamp you in and out and their stamps are quite chunky.

South Africa puts a sticker in your passport that takes about a third of a page and then they give small in and out stamps. They say they need blank pages but in reality they just need a blank half page.

Singapore stamps in and out but their stamps are small and they will stamp on pages that have been partly used.

If space is an issue, ask border guards to stamp in a particular place - often they oblige. I have also seen one person who conserves blank pages by putting post it notes on them that say "reserved for visas". Worth a try?