Tabletop gaming is best when it has tactile, physical elements to allow players to interact with and visualize their adventures.
A key element to engage players is the use of character and monster figures / figurines / miniatures. These 'minis' as they are called can be made of cast metal, 3D printed plastic (very popular today) or paper cardstock.
I think metal or plastic minis are cool, but they are super expensive, take up a lot of space, and are not very portable.
Paper miniatures (paper minis) however offer the best of all worlds. They can be packed flat, they can be printed quickly as required, they can be black and white to save money, and they can be resized to fit any scale.
And best of all there are sooooooooo many available on the internet.
Trash Mob Minis
One of my favorite styles of paper mini is the beautiful cartoon style created by Jess Jennings of Trash Mob Minis, available on DriveThruRpg and her Patreon site. Now while these minis are very reasonably priced, they do come in small sets of six so you could end up spending $60-$100 dollars for the whole set.
A Monster for every Season
Another favorite style of mine is Rich Burlew's paper minis based on his web comic Order of the Stick (OOTS), available on Gumroad. You simply cannot beat the fun factor and his 4 sets of character and monster minis cover just about anything you can imagine. Each set only costs $6 each, so even the collection of all 4 sets is only $24!
Minis for Many genres
David Okum over at Okumarts Games has created a huge range of different paper miniatures for many different game genres and they are available on DriveThruRpg.
'Intense' style
For those folks that like a more 'intense' looking paper miniature, Marshall Short of PrintableHeroes has a large variety to chose from over on his Patreon site and his own web site now at PrintableHeroes.com.
Plastic mini bases
While you can cut out and use the bases on the printable paper minis, I prefer to use a cheap plastic base. I find these plastic bases from Hedral do the job. They allow me to pack the paper minis flat with some elastic bands, and easily slide the bases on and off when playing.
I like to use colored bases for the player characters because it is more fun, and clear bases for the monsters.
You can find them on eBay or Amazon.
Using playing aids to engage casual board-game players
Don't under-estimate the power of tactile visual materials on a table to make something more fun. Folks that have never played D&D may find playing a game that is only 'in your mind' boring, but adding a few fun visual props that don't take themselves too seriously can make the game more accessible to casual board game players.
Print these paper minis up on paper or cardstock, and add them to a printed map and you have all the elements of a D&D board game which most people are familiar with.