Here's a link of Don and Peggy screencaps found on this spot:

Season 1
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Season 2
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2.08 A Night to Remember (No scenes between Don & Peggy in this ep.)
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2.11 The Jet Set (No scenes between Don & Peggy in this ep.)
2.12 The Mountain King (No scenes between Don & Peggy in this ep.)
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Season 3
3.01 Out of Town (No scenes between Don & Peggy in this ep.)
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3.03 My Old Kentucky Home (No scenes between Don & Peggy in this ep.)
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3.08 Souvenir (No scenes between Don & Peggy in this ep.)
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Season 4
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4.03 The Good News (No scenes between Don & Peggy in this ep.)
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4.10 Hands and Knees (No scenes between Don & Peggy in this ep.)
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