You can use some resources like computation directly and in unlimited amounts (e.g. living for unlimitedly long virtual times per real second inside a simulation). There are some physical limits on that due to speed of light limiting effective brain size, but that depends on brain design and anyway the limits seem to be pretty high.

More generally: number of configurations physically possible in a given volume of space is limited (by the entropy of a black hole). If you have a utility function unbounded from above, as it rises it must eventually map to states that describe more space or matter than the amount you started with. Any utility maximizer with unbounded utility eventually wants to expand.