I am the same, I never cared for young families in Sims, and the idea of a 100 baby challenge, You Couldn't Pay Me to Do It! lol
I love simple living challenge, and collecting myself. Though I have more packs, and use some of those packs to increase the challenge. Generally the same idea still can be applied to an extent. Like a Nature Lover collecting all fish, frogs, plants. etc. Here is my personal challenges I have lined up for myself, many parts can just be skipped if, you do not have the pack, many concepts can still be done (like instead of relying on Natural Living Skill, rely on Simple Living).