A microphone preamp/EQ is a great option to have if you are looking to sculpt a sound into the mix. With the addition of an EQ, you can take away muddy low frequencies when tracking a vocal, and add air to the top end. For drums, you can add a little sub to the kick drum, or attack to the snare while tracking, leaving less work to do in the mixing process.
Some mic pre/EQ combos are modeled after sought over tones from vintage consoles, such as the Neve 1073. With its signature preamp design, and the addition of its musically designed three band EQ, add air to any source with is 12 kHz shelf, attack and presence to the midrange, and depth and warmth to the low end. Also included is a hi-pass filter for carving out the muddy low end that often clouds a mix. Similar models include the Chandler LTD1, Vintech X731, and BAE 1073.
Look into tube preamp/EQ combinations such as the LaChapell Audio 583e. Offering input and output controls, so you can boost as much frequency as you want, then trim the down the output to not clip the converters of your audio interface. Equipped with three variable frequency bands to hone in on any frequency with the option to boost or cut. This model, as well as many others, have the option to patch into the EQ independently from the preamp, allowing you to mix and match different preamps and EQ, and add even more variety to your studio setup.
Others come in a more simple design like the Universal Audio 610. Get the great tube warmth from the 610 preamp section, but have the option of two independent frequency bands, with three selectable frequencies, and fixed intervals of boost or cut. In any model like this, the frequencies that were chosen are very musical and tend to sound good on any source you run through them. Sometimes adding one click of 10 kHz, and cutting one click of 70 Hz can make a vocal pop in the track.
Get with your Vintage King sales engineer to find the best mic pre/EQ for your studio setup.