There's no ERG equivalent on Labour's end. But there are a few Labour MPs who are staunch Leavers, either on a personal basis, or because they represent constituencies that voted heavily for Leave during the referendum, or because they're concerned about the damage that not leaving might do to the UK and its institutions.
As a result, a handful Labour MPs rebel at each Brexit vote. But note that the exact number of Labour rebels, and the reasons they rebel, varies from one vote to another.
For instance, 9 Labour MPs voted against Yvette Cooper's amendment on April 3rd. On March 25th's vote on having indicative votes 8 Labour MPs voted against the Letwin amendment.
The votes around March 13th are some of the most interesting for your question, I think. Only 2 Labour MPs rebelled against the amendment that insisted that the UK should not leave the EU without an agreement, at any time.
They were [Reject No Deal; Reject No Deal under any circumstances; Request a delay to Brexit]:
Stephen Hepburn Jarrow (Leave 62%) Aye Aye No
Kate Hoey Vauxhall (Remain 78%) Aye Aye No
During the same week, here's how the others who rejected Yvette Cooper's recent amendment voted:
Sir Kevin Barron Rother Valley (Leave 67%) - - Aye
Ronnie Campbell Blyth Valley (Leave 60%) Aye No -
Rosie Cooper West Lancashire (Leave 55%) No No Aye
Caroline Flint Don Valley (Leave 69%) No No Aye
John Mann Bassetlaw (Leave 68%) Aye - Aye
Dennis Skinner Bolsover (Leave 70%) Aye No No
Graham Stringer Blackley and Broughton (Leave 51%) Aye - No
(To clarify why I singled out the above, voting against the Cooper amendment at this point is a de facto no deal embracement for MPs, unless they make the unlikely bet that the EU will miraculously accept to keep the soap opera going, or the equally unlikely one that MPs will repeal Article 50 or pass May's deal in some form or another. The only reasonable excuse they can put forward to wiggle themselves out of not supporting it is by saying it's better to not tie the government's hands -- which, let's face it, hasn't exactly been Labour policy of late, if ever.)
I suspect these are more interesting that the No Deal motion that MPs voted on as part of a series of indicative votes (see JJJ's answer), because when the latter were occurring there were much more interesting options on the ballot (the MPs were using approval voting rather than their usual Ayes/Noes), and MPs were seeking a way out of the deadlock they were in -- even if they didn't necessarily approve what they voted to back.
Of the above mentioned MPs, I'd raise that Kate Hoey stands out somewhat as a very staunch Leaver IMHO -- it takes pumpkin sized balls to go against the will of your voters. Insofar as I'm aware she's the only Labour MP to put forward that a deal shouldn't be needed to begin with.
Here's another data point:
The three labour MPs who voted against extending article 50 today (Apr 9, 2019), a day prior to the EU summit to discuss it, are: Ronnie Campbell, Stephen Hepburn, Kate Hoey.