Changelog:
v1.0: Release
v1.1: PFRPG support
v1.2: Support for base + art subscription themes
v1.21: Readded PFRPG support as it was lost doing the last update
v1.22: Changed Charge from +1 to +2
v1.3: Compatibility update for ruleset changes
v1.4: Added exclusionsets to use the new ruleset features and add better compatibility
v1.5: Added compatibility with the Extra-Actions extension and changed some behavior in the extension itself
v1.6: Major rewrite
v1.7: Compatibility patch

What this extension does:
- All attack modifiers (all I know of in 3.5E) with the corresponding plus and minus
- Only modifiers which work together can be selected together
- Check wether the attack is melee or ranged (Shoot [into] Melee) doesn't work on melee attacks

Known minor nuisance:
Modifiers are not bound by character sheet but by user. This shouldn't impact actual gameplay but may irritate. Explanation:
https://www.fantasygrounds.com/forums/showthread.php?70979-Attack-Modifiers-Extension&p=655246&viewfull=1#post655246

Otherwise see the forum thread.