Many of the federal tax credits have annual limits per household, but those limits reset at the new year. You may want to plan which improvements you make in each year to maximize the tax credits you receive. This incentive calculator from Rewiring America gives some details on which incentives you qualify for and what the annual limits are.
This page from The Switch is On shows updated information for incentives in California The Switch is On - Incentives.
The documents linked below provide more details for the most common home electrification tasks.
Some of the California rebates (e.g. TECH Clean California) are allocated a fixed amount of money and are suspended when the money is fully allocated. These rebates may start again if new money is allocated. Check with TECH Clean California, The Switch is On, and knowledgeable contractors for information on when these rebates are/will be available.
California also provides the Golden State Rebates. These are funded by utility rate payers and overseen by the CPUC. Rebates are available for Smart Thermostats, Room Air Conditioners, and Heat Pump Water Heaters (240 Volt only).
You can save money by making your home energy efficient before other electrification tasks. Energy efficiency may allow you to use a smaller, less expensive heat pump for heating and cooling.
Insulation and Air Sealing Incentives
Heating, air conditioning, and heating water are usually the largest uses of energy in the home, and are most likely to require changes to your home's electrical system.
Heat Pump Heating and Cooling Incentives
Heat Pump Water Heater Incentives
Electrical Panels and Wiring Incentives
With the new Net Metering 3.0 rules in California it generally makes sense to install both Solar PV and Battery Energy Storage at the same time.
An alternative is to sign up for 100% Renewable Energy from your CCA. See here for details.