stablecoins vs USDC on ethereum mainnet, block 26,026,600 (2026-09-21 14:52 utc)
USDC itself: $0.9998 on coingecko

coin    v3 pool       spot  twap 10m       dev  liquidity  coingecko
USDT    0.01%      0.99982   0.99990    -1.8bp    40.8e15     0.9997
DAI     0.01%      0.99999   0.99990    -0.1bp  9494.4e18     1.0000
USDe    0.01%      0.99997   0.99990    -0.3bp  4777.4e18     0.9999
FRAX    0.05%      0.99203   0.99194   -79.7bp   275.8e15     0.9922 !
LUSD    0.05%      1.00707   1.00703   +70.7bp    11.9e15     1.0080 !
PYUSD   0.01%      1.00012   1.00010    +1.2bp   679.6e12     1.0000
crvUSD  0.3%       0.99704   0.99711   -29.6bp   558.4e15     0.9998
GHO     0.01%      0.99911   0.99910    -8.9bp   479.8e18     0.9990
USDS    0.3%       0.99932   0.99940    -6.8bp     6.0e18     1.0000

curve 3pool: 100,000 USDT -> 99,961 USDC (-3.9bp), 100,000 DAI -> 99,984 USDC (-1.6bp), virtual price 1.0398

! = at least 50 bp off the peg: FRAX, LUSD