I'm playing a Bosmer and plan on sticking to green pact and also not using soul gems, due to them not liking necromancy or the use of soul gems because of it.
The weapons that I can think of that come to mind are - Vladr's dagger, Mehrunes Razor, Skull of Corruption, Ebony Blade, Dawnguard rune axe and Hammer, Trollsbane, Hoksbane, Wuuthrad and Windshear.
Does Bloodskal blade need recharging and does anyone know any other weapons (especially bows and staffs).
Keening doesn't need to be recharged if you have around 25% Fortify Destruction enchantments. It's kind of unique in that it only has one charge, and cannot be recharged. But by getting a degree of Fortify Destruction, you can trick the game into thinking the cost is 0, which allows it to be used indefinitely. For most weapons, you'd need 100% Fortify Destruction, but because of Keening's unique 1 cost / 0 charge state, you only need enough to get the game to round down the 1 cost to 0. I'm not sure exactly where that cutoff is, but I know it's around 25%, if not lower. Its effect is pretty nasty, it has a cool backstory, and it would probably fit as an emergency melee weapon for a bowman/staff wielder.
Another one I didn't see mentioned yet is The Longhammer. Maybe not ideal for your build, but one of the best two handed weapons in the game if you're looking at damage per second. I'm fairly certain it's not technically an enchantment either, which means you could add another enchantment on top of it, or temper it without picking up the Arcane Blacksmith perk.
Also, Silver Swords and Silver Greatswords are in the same boat. Constant non-enchantment effect. They cannot be tempered though.
I thought Keening was 100% destruction reduction, if it isn't that's good to know. Never tried the Longhammer, it weighs 8 less than a regular orcish warhammer and according to wiki it can swing as fast as a one-handed weapon, is that true?
If it is, that sounds like it could be a real useful weapon .
It swings about as fast as a Silver Greatsword, which is the fastest two handed weapon in the game to my knowledge (maybe excluding the Bound Battleaxe). It has the highest DPS of any hammer, and possibly any two handed weapon period. And yeah, since it's not technically an enchantment, you can temper it, and combine with Elemental Fury, to get oodles of DPS output.
I haven't done any real testing with Keening; my basis for recommending it is from a thread in the discussion page for the Keening UESP article. You might want to run a few tests yourself rather than just take my word for it, but the guy on UESP seemed pretty credible to me.