Among those will be ECB president Mario Draghi
I've highlighted them in the calendar preview here, but here's a quick glance for your convenience:
0730 GMT - ECB's Coeure meets with fintech companies in Berlin, Germany
An event organised by FinLeap. No details if he is to give a speech or participate in any discussion.
0800 GMT - ECB's Draghi speaks in Frankfurt, Germany
Draghi is to give an address at "The ECB and Its Watchers" XIX conference. Details here.
0845 GMT - ECB's Praet speaks in Frankfurt, Germany
Praet will be at the same event as Draghi and he will be participating in a debate: "Assessment of QE and Challenges of Policy Normalisation".
0845 GMT - ECB's Angeloni speaks in Rome, Italy
He is part of the banking supervision board and will be giving a speech related to QE and tapering, and their effects on assets under management (AUM).
1045 GMT - ECB's Constancio speaks in Frankfurt, Germany
Constancio will be at the same event as Draghi as well. He will be participating in a debate: "The Pursuit of Financial Stability and Tasks for Monetary, Regulatory and Macro-Prudential Policies".
Those are for the European session. But at 1330 GMT there's also ECB's Villeroy due to speak in the same conference as Draghi & co, and at 1615 GMT we have ECB's Coeure back again speaking in Berlin in a panel on the topic of zero interest rate policy.
There's no details on Draghi's address, so I reckon he'll be delivering the welcome note or some sort for the conference. Not likely to be anything out of the ordinary, but you can't rule out Mr. D when he's on the mic, can you?