I've lived in Portland for a while now. I've written and lost numerous lists of recommendations over that time. Here's a list of stuff I like in town put somewhere I can stop losing it. I split the list up by area of town (and nearby areas).
Here's what the emoji mean, click one to filter just that category:
🥾📸⭐️ Lattourel Falls - good easy hike to upper fall, lower fall can be seen from trailhead
📸 Multnomah Falls - this is the iconic fall, you need to get a ticket beforehand online, we didn't think the hike to get on top of the fall was worth it
📸⭐️ Vista House - great view of gorge, right by road
📸 Columbia River Gorge Scenic Highway - bunch of falls and vista house along this, good morning trip gets really busy as the day goes on
🥾📸 Dog Mountain - hard hike, good vista, lots of wildflowers
📸 Horsetail Falls - one fall is right at the road, with wading pool, haven't done rest of hike
🥾📸 Beacon Rock - fairly hard hike, climbs a lot but isn't too long, cool view of gorge