It would be very helpful to have lookup fields as a custom field type.

There are a number of relatively obvious uses for something like this. Depending on one's situation, it may be important to record competitor(s) and/or vendor(s) for a deal. Those would be Companies, but one can only select a single company for a deal.

These sorts of custom field options are readily available in other Zoho products, competitive pipeline-type products, and low-code database solutions.

I understand the idea of trying to limit bloat and feature creep, but I think letting users make necessary connections in their data is important and probably on the right side of that balance.