This section is tough because the map is large, and, as with the last section, I should be upfront that I don't know all of it and that I'm generally more familiar with the electoral world (focusing on winning campaigns) than I am with advocacy (e.g., lobbying legislators or corporations). I'm also going to go into a brief description of campaign finance, but I'm not a lawyer so please don't rely on this for actual legal advice.
When it comes to elections, you have the candidate and the independent expenditures. The candidate side ("Coordinated Campaign") can work with the Democratic Party (national and state levels) to organize field work, messaging, policy, etc. The independent expenditures (“IE”) side can’t coordinate with the candidate or the party and instead operates on its own. Also, sometimes IE groups can coordinate with coordinated groups, with exceptions varying by state and by race (e.g., federal vs. state). The IE side often will include three categories of organizations: Super PACs and other advocacy groups (e.g., environmental groups, labor unions, women’s rights groups); non-partisan groups (e.g., Rock the Vote); and Party IE organizations (an IE group funded and staffed by the party). Each of these three categories can only coordinate within themselves and none of them can coordinate with the candidate or the party. (Confused? Me too. See "not a lawyer" above.)
You might ask what the difference is between work that happens on the coordinated side, and work that happens on the IE side. The answer is that it’s complicated. On the IE side, you have groups like Priorities USA Action, which raises money from large donors and mostly spends it on paid communication like TV or digital ads (as oppposed to direct voter contact, like a large door-knocking program). Other IE groups include membership organizations like Sierra Club and Planned Parenthood, which run a mix of direct voter outreach (e.g., door-knocking) and paid communication programs. Finally, there is organized labor, which runs primarily field-based member-to-member (as in, union members talking to other union members) programs and general voter outreach. These organizations are often coordinated through America Votes, which has its own in-house data management capacity. The coordinated side tends to be more associated with direct voter contact activities, such as canvassing and phone banking. However, even candidate campaigns may often allocate the majority of their expenditures to TV advertising. Outside of elections.
In terms of longevity, candidate campaigns usually wind down immediately after the election, but the party committees (the Democratic National Committee, the Democratic Congressional Campaign Committee, etc.) exist continuously and build capacity across cycles while assisting on candidate campaigns. Meanwhile, many IE groups exist and engage in substantial activity continuously. During the "off-year" or "odd-numbered" years (i.e., non-presidential and non-midterm election years), advocacy and non-profit organizations might engage in legislative issue advocacy, membership mobilization (like organizing protests or identifying volunteers), etc.
Almost every major organization, IE or coordinated, will have access to some sort of data and analytics capacity. Many organizations will have in-house "data" staff, who manage the inflow and outflow of data. Some coordinated campaigns will also have in-house analytics team, e.g. Hillary for America or the DNC. Most campaigns won’t be able to support a team of that size or scope. Instead, they’ll rely on other (larger) campaigns or analytics consultants to provide what they need. On the IE side, many organizations don't have their own analytics team, although some of the larger ones will. America Votes helps coordinate analytics products, e.g., sharing data, across multiple organizations. The AFL-CIO analytics team and the Catalist analytics team also provide a lot of analytics services (like model scores or analysis of specific problems) for members of the IE community.
When organizations don’t have an in-house analytics team, they’ll often turn to outside consultants. These consultants often come out of campaigns and, in theory, offer lower hours and higher pay than directly working for a candidate/campaign (at the cost of access). There are a host of analytics consultants, including but not limited to BlueLabs, Civis, Clarity Campaign Labs, HaystaqDNA, and Minerva Insights. Some of these consultants are more focused on left-leaning politics, but almost everyone will do some degree of corporate or otherwise non-political work to tide themselves over between elections. Methodologically, most of these organizations provide predictive modeling and strategy. On the experimental side, the progressive movement has the Analyst Institute, which conducts and disseminates research related to tactical strategy and serves as a central hub for meetings between practitioners (i.e., people who implement campaigns and other programs in the field) and analysts. All of these consultants will work in concert with strategy pollsters in order to provide information for campaigns.