NYMEX HH, NYMEX NN, ICE NG LD1 Henry, and ICE NG LD1 ICE Lots Henry are all financially settled vs the NYMEX NG final trading day settlement price. The only difference between the products (other than exchanges) is contract size. NYMEX HH is 10,000 MMbtu/month, NYMEX NN and ICE NG LD1 Henry are both 2,500 MMBtu/day and ICE NG LD1 ICE Lots Henry are 2,500 MMBtu/month. While NYMEX NN, the 'ICE look-a-like' used to trade it rarely has active markets now.
As such the NG-HH spread represents the physical delivery premium. This spread for the last several years has been around 1c/10 NG ticks but has deviated at times especially in the last few days of trading where in recent months there have been some much wider divergences. As stated previously the NG-HH spread trades in quarter ticks, or $0.00025 which is $2.50 per contract.
NYMEX HP, NYMEX QG, ICE NG Pen Henry, and ICE NG Pen ICE lots Henry are all financially settled vs the NYMEX NG settlement price on the day prior to the final trading day. This is also options expiration day. The only difference between the products (other than exchanges) is contract size. NYMEX HP is 10,000 MMbtu/month, NYMEX QG and ICE NG Pen ICE lots Henry are both 2,500 MMBtu/month and ICE NG Pen Henry is 2,500 MMBtu/day. NYMEX QG is obviously the eMini.
NYMEX list NG-HP spreads and HP-HH spreads but these are far less liquid than NG-HH.
Should be noted that the ICE products are fungible. If you Trading 1 lot or 2500 MMBtu/day of the ICE NG LD1 Henry for Jan21, what will actually hit your account is actually 31 lots, or 1 lot/day, of the 2500 MMbtu contracts. This also creates the interesting situation that an F/G spread, actually creates an outright position, since the number of days in each month is different! This can cause problems in fast markets as the anchor prices can be off-market, and hence the price of the outright delta can buy or sell can also be off-market.
Regarding the new(er) Clearport front end, I believe you will find that the contracts traded are not only the same products, but Clearport uses the same Globex matching engine. Most (if not all) Cleared Swaps in the Energy industry are long gone.