A paper which comes to mind is this one by Quentin Poole. The approach involves sophisticated statistics on a 10 km grid of plant observations.
The Swiss Mammal & Bird Atlases also have detailed accounts of how observation data were manipulated to create range and potential range maps. In Switzerland, altitude is a very significant factor so this must be take into account as well as simple 2-D geography.
Scientists in Latin America observing invertebrates where many species are poorly known, or undescribed, have rather more sophisticated approaches to sampling, simply because they have to. I’ve always meant to apply one of the protocols described in Neotropical Insect Galls in the UK to see what results I get.
I was looking at UK records of Trioza centranthi the other day, and for this species it is records far away which would help build up the picture. Until 2016 this insect was only known in coastal areas of Britain and Ireland, and then it was discovered about as far from the sea one can get in Leicestershire. Subsequently it has been found in many inland areas, but there are no records on iNaturalist for Eastern England, but I do know it is there because I have recorded it via another site (iRecord, which consolidates research-grade records from iNaturalist).