In some cases you can run a conventional non-BOOST 1X or 2X crank. The Race Face NEXT 1X and other Cinch system 1X cranks are dual compatible between standard 142mm and 148mm Boost rear ends. Some smaller chainring combination 1X (30 and 32T) Shimano XT and XTR 11 will also work. In some cases 2X standard cranks may also work with 24/34, 26/36 and 22/36 combinations. Shimano’s new 11 Speed XTR and XT standard cranks feature both 24/34 and 26/36 chainring options which work perfectly with the 429 trail frame as Shimano’s chainline dimensions already tend to run wider than others in the market. There may be other 2X non-boost cranks available that will work although it is dependent on specific chainline and chainring size. If the chainline is not out far enough, the front derailleur clearance may be tight when shifting into the small ring as the front derailleur mount on the 429 Trail is also shifted outwards to accommodate the BOOST design.
Additionally, you cannot run cranks designed specifically with a narrower Q Factor such as XTR Race 158mm Q factor crank and the SRAM XX1 156Q crank (In fact, for any SRAM 1X cranks, you need to run their specific BOOST version of the crank).