Here’s my grade of well-balanced or not well-balanced mods, with some descriptions. at least this is how I feel about some mods being fair or balancedwhen I tried them.
Kelsey NPC – Has a couple of encounters attached that are balanced. He's not superpowerful, either. Overall it fits within the game, Balanced.
Banter Packs – Just banter so of course it’s balanced
Unfinished Business – Balanced
Improved Oasis II- Balanced
Kensai Ryu’s Restored Drow Innate Abilities – A little tougher but balanced
Sim’s Miscellaneous Tweak Pack (DingOTweak)– Some of it, like removing Summoning Caps can unbalance the game, but something like Improved Goodberries makes them better without unbalancing the game. Overall balanced.
Iron Modder 1 Greyfain’s entry – Balanced
Turnip Golem Encounter – Balanced
Cal-Culator – An item, Balanced
Cleric Remix – Seems unbalanced as Clerics get a special ability at each level, but they lose a spell per level and some spells are removed all together, including some precious healing ones. The ones I tried, Viconna and Anomen were balanced.
Dark Ritual – 1st encounter is very hard (had to use ctr+y), encounter in Windspear Hills is normal difficulty. Also adds some weapon upgrades that can be a little more powerful, but not too bad. I’ll say this one is unbalanced because of the first encounter is too hard.
Solaufein NPC – Unbalanced, He's superhuman and the encounters are way too hard.
Totemic Cernd – Balanced
Ascension – Very Hard final encounter. This is probably unbalanced as it’s too hard. The rest of the improved battles and extra abilities are balanced.
Planar Sphere Return Mod – Balanced – Adds some different spells and encounters, not sure if I am finished with all the encounters, though.
The Darkest Day – Unbalanced because it allows you to get so much loot and experience the rest of the game will be a bore.
Ease of Use – Kinda unbalances the game. But, most are just to make some parts of the game better or easier. I’ll say Balanced.
G3 Tweak Pack – many stuff can imbalance the game, but a lot don’t. If you use the ones that don’t its balanced.
Rogue Rebalancing – makes them tougher, but they were nerfed initially. So I say Balanced.
Subraces – Balanced
Bag Bonus – kinda unbalanced. But more ease of use. I say Balanced
Freedom’s Reign/Reign of Virtue – It has some unbalanced item drops (shadow Dragon for example). But the stores are balanced as they don’t offer any super powerful items. I’m 50-50 on this one.
Improved Horns of Valhalla – Makes it more realistic – Balanced
Munch Mod – it’s been a while, but I think there are some super powerful items in this one. Items cause it to be unbalanced.
The Magnificent Magic store – Not super unbalanced, but the items are powerful nevertheless. Unbalanced.
Item Upgrade – Some are overpowered, some are not. 50-50 on this one.
The Unusual Oddities Shop – Meant to be Unbalanced. Super items.
Underrepresented Items – I found these to be fair. Balanced.
Tactics – Some are unbalanced as they are way to hard, Improved Ilych, The Ritual, Improved Sahuagin City, Improved Bodhi and Irenicus, Karoisan the Acid Kensai, Improved Twisted Rune, Improved Kangaxx, smarter Mages and Liches and I hear the druid Grove (haven’ttried It) is ridicously hard. And these two are unbalanced because they give out too much experience and too much gold and items: Random City Encounters and Random Wilderness encounters. And one I find boring because all the trolls are now spirit trolls (and the final fight can be a little hard) Improved Torgal. But I like all the others in his list and I feel they add good stuff to the game and are balanced.
Basically I don’t like super hard encounters that require cheese tactics or cheating to get through, and I don’t like super powerful items. The ones I say are balanced may be tough, but not too tough, and the items that are included don’t drastically change the game by making you into a superhero, but they might be a little powerful.
Hopefully this helps as I always wanted to know someone's opinion on a mod before I tried it.
Btw, I’m sure I forgot a few.