Hello,
It depends on what you want to simulate.
On this page of the EDUCYPEDIA , you will find several links to them:
http://educypedia.karadimov.info/electronics/easoftsim.htm
There are more pages to electronics software over there:
Analog
Antenna design
Audio
Audio tone generators
Digital
Loudspeaker design
Measurement
PCB design
RF Antenna design
RF software
Stripboard Layout Software
Bertus