There are only 120 minor league teams in 2021 thanks to Rob Manfred and MiLB re-alignment. The Angels will have their foreign league affiliates still as well as rookie ball in Arizona. The big change comes with A and and High A.
So the IE 66ers move from High A to Low A which is big for them. It will, however, allow the Angels to see newly drafted players sooner and closer to home. The Orem Owlz rookie team is gone, as are the Burlington Bees. Both of those teams are no longer part of Minor League Baseball.
The new team in the mix is the Tri-City Dust Devils based out of Pasco, Washington. Pasco is near the Oregon border about in the middle of Washington State. They will play at Gesa Stadium.