If your wantlist had a wantlist, it would probably pick out a handful of cards that you've potentially never seen before or just too unobtainable unless you've hit the lottery. Over the past few months on eBay, there have been a slew of incredibly rare Marino cards that NEVER come up for sale, and they're reaching incredible prices.
Take for example, possibly the most recognizable and sought after card set of the 1990s, the 1997 Skybox Metal Universe Precious Metal Gems Green. Serial numbered to 150, only the first 15 were issued in green. It sold for $4,550 on October 17. I scanned my wantlist, there's no other card that would command this kind of money. This is the most expensive Marino card you can own, and certainly an investment piece.
Equally recognizable for its use of bright neon colors on acetate, are the 1998 Skybox E-X2001 Essential Credential Future and Now sets. Limited to just 61 copies between the two sets, 53 exist for Marino in the Future set and only eight in the Now set. Depending on the players card number in the 60 card set, the serial number decreases from 1-60 for the Future set, and increases from 1-60 for the Now set. A Futures version sold for $888 on 10/23. Although the Now version for Marino is rarer and would probably sell for more, I'm not sure if its neon yellow colors would look as sharp as the Future version. If I had a choice, I'd go for the Future.
Skybox continued the parallels the following year in its 1999 Skybox E-X Century Essential Credentials Future and Now sets. With slightly increased print runs for Marino--66 for Future and 25 for Now--and a change in design, the 1999 set does not warrant the sky high prices seen for 1998. A Now version recently sold on 11/3 for several hundred dollars (eBay hid the price since it was a BIN, but I would imagine it sold for $400-500). The Future version #/66 can be had in the $150 range.
Lastly, one of the underrated late 90's sets that doesn't get as much notoriety as the top two sets is the 1998 Upper Deck Black Diamond Premium Cut Horizontal Quadruple set. Most of the players in this set can be easily obtained--except for Troy Aikman and Marino. For them, the insertion rates were much harder at 1:22,500 packs. And according to my records, only 10 copies were made. The example below was snatched up by BIN on 10/7, and although the price is obscured I know an offer north of $300 was declined, so I'd estimate the final sale price was around $500.