so besides the bard's jack of all trades which grants 1/2 proficiency to all non-proficient skills, how would one obtain bonuses to ability checks that don't use skills.
Technically anything that grants a bonus or advantage to “ability checks” would fit the bill. This can include the guidance and foresight spells, Tides of Chaos (wild magic sorcerer), Bardic Inspiration (bards), and others would all work
War Magic Wizards can add their Int bonus to Initiative. Gloom Stalker Rangers add their Wisdom and Swashbucklers add the Charisma. Besides that and whats already been mentioned, any items that would raise abilities would of course raise your bonus when using that ability.
so besides the bard's jack of all trades which grants 1/2 proficiency to all non-proficient skills, how would one obtain bonuses to ability checks that don't use skills.
The Champion fighter’s Remarkable Athlete feature gives you half proficiency in otherwise non-proficient strength, dexterity, or constitution checks.
A Stone of Good Luck (Luckstone) would do it, I believe.
Guidance cantrip.
Technically anything that grants a bonus or advantage to “ability checks” would fit the bill. This can include the guidance and foresight spells, Tides of Chaos (wild magic sorcerer), Bardic Inspiration (bards), and others would all work
War Magic Wizards can add their Int bonus to Initiative. Gloom Stalker Rangers add their Wisdom and Swashbucklers add the Charisma. Besides that and whats already been mentioned, any items that would raise abilities would of course raise your bonus when using that ability.
Higher Ability Scores....
Creating Epic Boons on DDB
DDB Buyers' Guide
Hardcovers, DDB & You
Content Troubleshooting
Tools.
...
No, seriously, tools use Ability Checks. If you're proficient with the Tool, you get your Proficiency bonus to that check.
Picking a lock, for example? Dexterity (Thieves' Tools).