Hulk 181 is always going to be hot in any grade no matter what and it has never gone down in value as far as I can tell…Even in the mid 90’s it still climbed slowly but surly. If you could look around and buy an
un-restored, complete CGC 6.5 for around $2500 you would probably be very happy with your return two plus years down the line. It also depends on how long you intend to keep the investment book. If it’s five or more years Hulk 181 is the best bet out of them all since he will probably be hitting the MCU within that time frame.
Giant Size X-Men #1 is still undervalued in my opinion. Once they officially join the MCU forget it, the book will spike bigtime and keep growing faster than it is now. For that one I would say a 7.0 or better if you can swing it, but any grade is a good bet, really. I’m seriously considering upgrading my 4.0. I didn’t get it for an investment, more of just to have but if I’m going to upgrade the time to do it affordably is closing.
Moon Knight should still have some legs as a good investment but Werewolf by Night #32 has seen some serious increase in the past 18 months. Still room to grow but for a strict investment an un-restored 8.0 or higher.
The last one I would consider is the Eternals. Right now that series is in a bit of a lull and there are some pretty good prices out there. For investment only I would stick with 9.6 and higher for this series.The price variants as well as the Black Knights first appearance (Avengers 47 and 48) in higher grade grade are good bets moving forward. Now is a good time to buy before the movie tailors hit.