Skubana, TradeGecko, Zoho Inventory, Infoplus, Dear Systems, CoreCommerce, Cin7, DSCO, Nexternal, and Unleashed are a few that immediately come to mind, but there are tons more out there. There are lots which are also an ERP or WMS rolled into one, but since Stitch Labs was not that I tired to list ones that were mostly or exclusively similar to Stitch Labs.