They can become huge. Some of them get big by making sprouting copies of themselves, which are sometimes called pups. Each one can be removed and planted elsewhere, where it will eventually develop its own offshoots. (They also reproduce with flowers, pollen, and seeds. )
This Haworthia is about 4″ tall.
Here’s part of a colony of a similar plant. Given enough space, it would probably spread indefinitely.
There are succulents that grow into very big plants. Jade plant, aka Money plants (Crassula ovata, usually) are easy to grow from cuttings and often change hands when small.
In a warm enough climate, they can become very big.
The ones that look like little stones (Lithops) do not grow into boulders. They do the colony thing. Here’s one of my favorite Lithops.
In time it would create a spread like the one below, which is another Lithops species.