If you have a generous DM, see if he will allow this. I made it for my own campaign. Basically gives a boost so you can get a familiar on par with what warlocks get. Or, if your a warlock, something cooler. Plus it makes the familiar slightly survivable, if you get fireballed.
Improved Familiar
Prerequisites: Ability to acquire a familiar. Allows spellcasters to acquire a more powerful familiar.
• You can acquire a familiar of any tiny or small creature of up to CR 1.
• You are considered to be in contact with your familiar for the purpose of shared spells, as long as it is within 1 mile of you. You and your familiar can communicate with each other telepathically at a range of up to 1 mile.
• You familiar has abilities and game statistics determined in part by your level. Your familiar uses your proficiency bonus rather than its own. In addition to the areas where it normally uses its proficiency bonus, it also adds its proficiency bonus to its AC and to its damage rolls. It also becomes proficient with all saving throws. For each level you gain after 1st, your familiar gains an additional hit die and increases its hit points accordingly. Whenever you gain the Ability Score Improvement class feature, your familiar also gains a +2 attribute improvement. Your familiar has a personality trait and a flaw.
• A familiar bestows expertise (double proficiency modifier) in one skill or tool. The skill is associated to the variety of familiar (eg., Cat: stealth. Monkey: acrobatics. Squirrel: sleight of hand , etc.)
• A familiar bestows a special ability upon its master. This ability is variable, and depends on the type of familiar. (eg., A psuedodragon or imp bestows magic resistance; a quasit bestows devil’s sight, etc.). Consult your DM or a creatures Monster Manual statistics for specifics.