I did not file an amended return for my unemployment tax. I filed before the new American Rescue Plan. When should I see my additional refund on the $10,000.

[VolvoGirl]

If you have filed. The IRS will recalculate your return for the new unemployment exemption for you. There is no need for taxpayers to file an amended return unless the calculations make the taxpayer newly eligible for additional federal credits and deductions not already included on the original tax return.

They are starting to go out. See this new IRS article May 14, 2021
https://www.irs.gov/newsroom/irs-begins-correcting-tax-returns-for-unemployment-compensation-income-...

You may need to amend your state return,
https://ttlc.intuit.com/community/state-taxes/help/do-i-need-to-amend-my-state-return/00/2134732

[DoninGA]

There is not an additional refund of $10,000. 

The unemployment compensation exclusion is for excluding up to $10,200 from your income on the tax return.

The IRS is calculating the tax refund based on the exclusion and sending refunds starting in May and then throughout the summer for all those who are eligible for the exclusion.

See this IRS website for information - https://www.irs.gov/newsroom/irs-sending-more-than-2-point-8-million-refunds-to-those-who-already-pa...