have You looked into the sample block files in the Solid Edge folder ?
C:\Program Files\Siemens\Solid Edge 2019\Sample Blocks\Electrical
There are several block drafts including alot of symbols.
And if they are not included, then You can use any vlock library from Autocad (DWG/DXF) and if they are not available too there, then You can create Your needed blocks Yourself very easy.
I have copied the path to them: