Temporary property tax and energy cost rebates application and requirements can be found here: https://www.ontario.ca/page/businesses-get-help-covid-19-costs.
There is also the COVID-19 Energy Assistance Program - Small Business (CEAP-SB) for utility bills, can be found here: https://www.oeb.ca/rates-and-your-bill/covid-19-energy-assistance-programs/covid-19-energy-assistance-program-small