Latex tubes are perhaps an option, as a sort of halfway house between butyl inner tubes and tubeless.
They are supposed to be better than butyl tubes for rolling resistance and comfort, which I believe after using them.
This site has some data that confirms my empirical belief, at least as far as rolling resistance is concerned:
https://www.bicyclerollingresistance.com/specials/tubeless-latex-butyl-tubesSome manufacturers also claim better puncture resistance, but I don't believe that.
Downsides are that they need topping up much more frequently than butyl, they are generally more expensive than butyl, and after a few years they perish and need replacing, whereas butyl tubes can last for many years.
Advantage over tubeless is no need for sealant or special inflation boosters, and just as easy as butyl tubes to replace at the roadside. Most manufacturers don't recommend patching them, but I do this and it hasn't posed any problems.
I run latex tubes on my Thorn Raven heavy tourer with 2" x 26" Marathon Supremes, my Thorn Raven Sport Tour with 1.35 x 26" Kojaks, and my lightweight derailleur bike with 28x700C Schwalbe One tyres.
I haven't bothered on my utility bikes, as I reckon the performance gain isn't worth the hassle of the more frequent reinflation required.
