Note: We all know that Monk wore the same thing in practically every episode, but Natalie Teeger’s wardrobe also got recycled quite a bit. I actually liked this aspect of the series, since it’s obviously much more realistic that someone would wear the same clothes over and over again instead of turning up in a new outfit every day.
Here are some of the items (excluding jackets and coats) that pulled double duty for Natalie in Seasons 3 and 4. (There might be more; these are just the ones I happened to notice.)
Purple t-shirt:

In bathroom scene in "Election"...

...and in tag of "Mrs. Monk"
Blue v-neck sweater:

In debate scene in "Election"...

...and in tag of "Other Detective"
Green mock turtleneck sweater:

In tag of "Election"...

...and in party scene in "Secret Santa"
