I wanted to add to this:

• The OpenEI Utility Rate Database is helpful for finding real ToU blocks, ie. ratios of pricing for peak, mid-peak, off-peak, etc. blocks of the day.
• For historical real-time pricing (RTP) and day-ahead pricing can be found directly from several ISO/RTOs. Here is what I have found:

1) New England ISO raw historical data

2) New York ISO raw historical data

3) PJM ISO Data Miner2 API and raw historical data

4) Texas ERCOT raw historical data

• And some miscellaneous sources of historical electrical pricing data I've found:

1) Ameren, in PJM

2) ComEd, in PJM

3) Engie various ISO/RTOs

4) Energy Online various ISO/RTOs

5) Altadata Energy paid API