You do not state what type of PPL training you are refering to.
Lets assume you mean EASA PPL training then the reference is in AMC1 ORA.ATO1.35. It does not specify any particular instruments.
AMC1 ORA.ATO.135 Training aircraft and FSTDs
ALL ATOs, EXCEPT THOSE PROVIDING FLIGHT TEST TRAINING
(a) The number of training aircraft may be affected by the availability of FSTDs.
(b) Each training aircraft should be:
(1) equipped as required in the training specifications concerning the course in which it is used;
(c) The fleet should include, as appropriate to the courses of training:
(1) aircraft suitably equipped to simulate instrument meteorological conditions (IMC) and for the instrument flight training required. For flight training and testing for the instrument rating, an adequate number of IFR-certificated aircraft should be available