Of the people I've played DnD with, I played with an arborist who played a Druid (Moon Circle), a PhD playing a Wizard (Divination School) and an engineering grad who's playing an Artificer (Artillerist). It should be no surprise that, for me and others who shared a table with them, these players were really able to bring that extra 'something' to their characters from their professions/interests/studies.

Share with us the characters you've come up with that drew on your personal expertise

I should imagine there'll be more than one lawyer among us who's played a fiend before 🥴...

I personally have an extremely useful degree in Ethnomusicology (the study of music through peoples; the study of peoples through music). Having studied music from around the world, I decided to stop putting it off and finally got around to making a bard, where I would normally default to Rogues/Sorcerers/Monks. I'll post him shortly.

Concept

I'm putting the finishing touches on a College of Spirits (UA) Bard, Human, and am very excited to make it work. I've decided to base him on the bardic cultures and religious/spiritual practices found in Africa and the Caribbean, as I know of a wealth of rich bardic and spiritual cultures to draw upon from my degree. The character will have a lawful-neutral alignment, where themes of ancestral power, possession, rites & sacrifices, bargains and the price of breaching, purification and pollution, will be treated by this character as a yin & yang of balance and the way (e.g. necromantic magic is not inherently evil; there are kind and malevolent spirits; deities are complex and contradictory etc).

Aesthetics & Inspiration

Here are the musical and cultural inspirations behind this character:

• Being a bard –a College of Spirits Bard no less– this character will spout stories, parables and proverbs at any opportunity that presents itself. I'll be drawing on the many tales of Anansai the Spider Man, while also paraphrasing a wealth of Swahili proverbs (in English) as the language is very well known for being highly poetic and expressive
• The Griot/Jeli of Mande culture (West Africa: Senegal, Mali etc) are historians, storytellers, praise singers, poets and mediators, best known for their kora music. The character's name is drawn from common male names among this culture.
• The Gnawa, who have historically  lived in the Sahel (North Africa: Northern Mali, Morocco etc), are sufis that fuse together west-African spirituality and Islamic beliefs and practice musical spirit possession rites.
• The Azmari (East Africa: Ethiopia, Eritrea) are musical bards, known for their satirical musical social commentaries and have historically drawn the laughter of the people and the ire of rulers and politicians 
• The Voodoo and Vodun beliefs are found in West Africa and the Caribbean. Many of us will probably associate 'voodoo' with 'evil' thanks to christianity (much like much like paganism) and colonialism, but it is just one of many of human belief systems throughout the ages and the character's alignment will be Lawful-Neutral, which I think would fit how these belief systems might view themselves

Background

• I went for a Custom background, which I named Tikori Jnawi. Jnawi is the name for those that hail from the bardic caste that I came up with, while Tikor is the world in a pre-colonial/Afropunk-inspired RPG setting called Swordsfall that I came across while researching for this character (the setting looks exciting!)
• I've chosen Far Traveler Background Features for him, as I expect any campaign he is played in won't focus on areas culturally and geographically comparable to North-West Africa. He'll be different to most folk, that's for sure.
• I've also chosen Personal Characteristics from Gladiator, Far Traveler and Acolyte
• The background includes proficiencies in Persuasion, Medicine, the Herbalism Kit and Poisoner's Hit, allowing him to lobby the powerful, mediate with diplomacy, provide council, as well as perform the rites of purification, sacrifice and appeasement that his spiritualist beliefs require

Mechanics

Character in DnD Beyond

• Far from a powerbuild, I've been keen to give him a strong WIS stat to match his wordiness and bolster his Insight skill
• He's currently sitting in DnD beyond as a Bard 6 / Cleric 1 (domain TBC)
• I uncomfortably felt compelled to add Cleric, as he ended up with a laughable HP & AC combination and thought some medium armour/cleric spells would improve his terrible survivability
• I've never really liked the Warlock class much, since I feel it's a really cheesy multi-class and think DMs rarely present Warlocks with difficult obligations from their patron, but I'm now considering remaking him Warlock 1 (hexblade) / Bard 6 for mechanical purposes. Yet to be done.
• I picked up the Magic Initiate - Druid feat for some more animistic flavour and as a means of making his high WIS combat-worthy
• I've also given him Ritual Caster, as rituals and rites will feature heavily in his roleplay
• I intend him to use a knobkerrie (club/quarterstaff), and/or a yklwa, possibly with a shield
• Spells are thematic, such as Bestow Curse, Speak with Dead, Vicious Mockery, Zone of Truth, Healing Word, Purify Food and Drink, Speak with Animals, Unseen Servent etc.
• His spell gained from the Spirit Session feature will be, for now, Revivify

(Honestly, recommendations on how to build this character also welcome!)

I personally play several instruments from around the world, so intend to bring some live music to the table. I think it might be a nice touch to accompany the subclass's Tales From Beyond feature, giving a brief medley before each story is told.

Sadly in 5e, there's not much of a place for system maintenance, system security, and web design and implementation. Illustration also has limited application.

So, I do what I never do IRL: punch people - usually in the junk because Halfling.