I have a shared database with different applications needing the same base data but also additional data. Without creating a giant master table with all possibilities and without creating 1:1 relationships, how do I model the data?

e.g.

MasterOfficeTable
officeID (PK)
name
phoneNumber

Application 1 keeps track of supplies per office and needs office data with supplies information (# of pencils, pens, etc) for reports.

SupplyOfficeTable
supplyID (PK)
officeID (FK)
supplies

Application 2 keeps track of energy usage per office and needs office data with energy usage information for reports.

EnergyOfficeTable
energyID (PK)
officeID (FK)
energyUsage

Application 1 does not care about energy and Application 2 does not care about supplies.

How do I use data from MasterOfficeTable to supplement the office details for the supplies and energy data?

I don't quite follow. Surely your "supplies" data doesn't have a 1:1 relationship with "office", and nor does "energy usage"? Why don't you just have the 3 tables as shown, with office as the master of both supplies and energy usage tables?